Cold moulding press

ABSTRACT

In cold moulding or pressing of workpieces, in particular workpieces of elongated form having a longitudinally applied moulding pressure, rough workpieces or blanks vary in volume and there is provided means for shearing off an unwanted overlength portion of the workpiece before the final moulding to avoid faulty deformed mouldings. Preferably, the blank is formed into a roughly moulded workpiece in a first die, the workpiece is transferred to a second die and moulded to its final basic shape and then trimmed by a shearing device, formed by a movable portion of the die and containing the over-length portion of the workpiece, displacing with respect to the main portion of the die. The workpiece can then be transferred to a third die for final moulding to the finally required form, the correct volume of material for the finally required form being supplied by the workpiece leaving the second die.

1 Mar. 28, 1972 [54] COLD MOULDING PRESS Rudolf Liebergeld, Gernotstrasse 51/55, 85 Nurnberg, Germany [22] Filed: Sept. 3, 1969 [21] Appl.No.: 854,988

[72] Inventor:

[30] Forelgn Appllcatlon Prlorlty Date Mar. 15, 1969 Germany ..P 19 13 215.1

[52] U.S. Cl ..72/34l, 72/344, 72/354,

72/377, l0/86 F ..B2lj 13/02, B2lj 13/14 [51] Int. Cl.

3,183,702 5/1965 Zittell ..72/339 McClellan ..72/338 Bertoglio ..72/353 Primary Examiner-Richard J. Herbst Attorney-Holman and Stern [5 7] ABSTRACT In cold moulding or pressing of workpieces, in particular workpieces of elongated form having a longitudinally applied moulding pressure, rough workpieces or blanks vary in volume and there is provided means for shearing off an unwanted overlength portion of the workpiece before the final moulding to avoid faulty deformed mouldings. Preferably, the blank is formed into a roughly moulded workpiece in a first die, the workpiece is transferred to a second die and moulded to its final basic shape and then trimmed by a shearing device, formed by a movable portion of the die and containing the over-length portion of the workpiece, displacing with respect to the main portion of the die. The workpiece can then be transferred to a third die for final moulding to the finally required form, the correct volume of material for the finally required form being supplied by the workpiece leaving the second die.

4 Claims, 8 Drawing Figures COLD MOULDING PRESS The invention relates to moulding, and in particular workpieces of bar-shape, with discrepancies in the uniformity of their volumes or sizes into finished pressed pieces with uniform volumes. In particular, cold workpieces can be moulded. Moulding pressure is applied in a longitudinal direction along the axis of the workpiece in a single processing machine, fitted either with a single pressing die or matrix and at least two consecutively operated pressing rams, or with at least two such dies and at least one corresponding pressing ram for a total of at least two consecutive pressing actions of the workpiece.

The manufacture of finished pressed pieces having certain and predetermined dimensions, that is to say, finished pressed pieces of uniform volume and size, requires in itself the use of rough workpieces of uniform volume. But since, in general, the bar material produced particularly by rolling processes from which the rough workpieces are to be obtained is made to a wide range of diametrical tolerances, it is only by means of uniform length cutting that rough workpieces can be obtained in a form showing only a limited amount of discrepancy in their mass or dimensions. As a result of this, the barshaped finished pressed piece, by observing the prescribed diameter dimensions governed by the die used, will vary from its specified length by an amount depending on the diameter of the end further away from the pressing ram. In this way, all finished pressed pieces having such discrepancies must undergo further processing for the specified length to be eventually obtained. But if it is necessary during any stage of the pressing process to use a stationary counter-pressure block in opposition to the pressing ram as a support for the workpiece, the adjustment of the counter-pressure block can be altered subject to the amount of the length tolerance of the workpiece or the workpiece can be cut to its specified length in advance.

According to the invention there is provided a press for moulding workpieces, comprising a die having a main portion forming a first shear member and a movable portion forming a second shear member, both said portions forming a moulding bore, a pressing ram arranged to move axially with respect to the moulding bore, ejector means for removing moulded workpieces from the moulding bore, and means for operating the second shear member, whereby the second shear member is movable generally perpendicularly to the axis of the moulding bore for shearing a portion from the workpiece when contained therein.

The invention can provide a cold moulding press, with which it is possible to manufacture finished pressed pieces of uniform volume and size from rough workpieces having dimensional discrepancies without the disadvantages and difficulties experienced with already known cold moulding presses. At the same time the constructional requirements and the outlay for the acquisition of the press can be considerably lower than those of other known cold moulding presses.

In accordance with the invention, the workpiece will not be cut to length by the shearing device formed by the two shear members before the first, or after the last pressing action, while the workpiece is located in the corresponding die. Another advantage of this process is that it can result in a considerable saving of extra costs. Also the entire process may be accelerated; there are no delays in the processing stage, as the length cutting can be effected within the moulding die without any time loss between two pressing cycles.

Whereas it is necessary for the execution of at least one pressing cycle of the workpiece for the pressing ram to act against a fixed counter-pressure block during the pressing process as a support for the workpiece, the length cutting of the workpiece should be carried out before this process using the counter-pressure block. Waste pieces inevitably arising in the case of uncut workpieces that have been wrongly positioned in the pressing die and subjected to the influence of the counter-pressure block in subsequent deformation, can be avoided by this embodiment of the cold shaping press. In addition to this basic avoidance of waste, savings are also made in that the necessity of a thorough check of all finished products for the purpose of separating waste may be eliminated.

For the length cutting of a workpiece having a volume as uniform as possible, particularly before the deformation process, with the use of the counter-pressure block, a further embodiment of the invention can provide for the workpiece to be cut to length immediately before the deformation process by means of the counter-pressure block in the appropriate die for this deformation, or, if it is preferred, after the above stated process of deformation in the appropriate die for this deformation. As a result of the cutting of the workpiece at one of these two points of time, the workpiece is cut at a stage preceding the deformation process as much as possible, i.e., in an already more or less greatly reduced diameter size range, so that any tolerance arising in the longitudinal extension of the workpiece during this cutting process if of very little if any importance in the further processing of the workpiece.

The invention provides for a cold shaping press, in which the die which contains the workpiece during the shearing process is divided across the longitudinal axis of the workpiece at the exact cutting position and in which one of the two part pieces, preferably the piece comprising the end of the workpiece that is to be cut, is retractable from its position before or during the cutting process in the course of the pressing process and is returnable to its original position after the cutting process and the removal of the cut end. In addition to the above aim, the division of the pressing die has the additional advantage of an easier fabrication of the pressing die.

A cold moulding press according to the invention is illustrated by way of example in the accompanying diagrams, of which:

FIG. 1 is a longitudinal section through a cold moulding press with three pressing dies and one cutting or shearing device for shearing the workpiece to length;

FIG. 2 is a section along the line II II of FIG. 1;

FIG. 3 is a section across the single pressing die, showing in the left-hand portion a workpiece sheared to length and correctly positioned, and showing in the right-hand portion a workpiece not sheared to length not correctly positioned both before the pressing operation;

FIG. 4 is a section corresponding to FIG. 3 with the same two different workpieces in each half, both after the pressing operation;

FIGS. 5 and 6 show a section through a pressing die, FIG. 5 showing the die with a workpiece sheared to length, and FIG. 6 showing the die with a workpiece not sheared to length, both workpieces being shown after the pressing process;

FIG. 7 is a cross section through a pressing die containing a workpiece that has been sheared to length, showing the workpiece in the left-hand portion before the pressing process and in the right-hand portion after the pressing process; and

FIG. 8 is a cross section through the pressing die of FIG. 7 containing a workpiece that has not been sheared to length, again the left-hand portion showing the workpiece before the pressing process and the right-hand portion after the pressing process.

The cold moulding press shown in FIGS. 1 and 2 has three consecutive pressing dies or matrices, l, 2, 3. Above the pressing die 1, a rough workpiece 4 is shown in chain dotted lines, which workpiece 4 after being inserted into the pressing die 1, takes up the position shown in the left-hand portion by the two broken lines 5. After the first pressing process, i.e., that in pressing die 1, has been carried out, the workpiece 4 adopts the shape 40, which is clearly shown in the right-hand portion of the pressing die 1. The line 6 shows the lower end of one of the workpieces subjected to the first pressing process, which, as a rough workpiece, did not show any discrepancies of volume; line 6a shows the corresponding end of a workpiece treated in the same manner, but which did have a volume discrepancy in its rough state. The distance of the line 6a from the line 6 varies according to the degree of the discrepancy.

The cold moulding press has a frame which holds the pressing dies 1, 2, 3 by means ofa horizontal support 14 in the center. Above the pressing dies 1, 2, 3, there is a hydraulic unit 16, which is connected to a crosspiece 17. On this crosspiece 17, are attached three inverted pressing rams 18, 19, 20, which can be rammed into their respective pressing dies 1, 2, 3.

In the example shown in the diagrams, the end portion 7 of the workpiece subjected to the first pressing process is subjected to further deformation in pressing die 2. Whereas the left-hand part of this pressing die is shown without a workpiece therein, a workpiece 4b, already undergoing further pressing, can clearly be seen in the right-hand part. Here too, as in the first pressing process, the two possible ends 6, 6a of the workpiece are shown. The pressing die 2 comprises a main part 2a and a movable part or shearing anvil 2b. The movable part 2b is in the form ofa shearing sleeve that is movable perpendicular to the axis of the bore of the die, with the top face ofthe movable part adjacent the bottom face of the main part. The movable part 2b has a bore 21. Through the shearing action of the movable part 2b acting with the main part 2a after the pressing process in the pressing die 2, the end portion 8 of the workpiece projecting into the bore 21 of the movable part 2b is trimmed to the specified length, the plane of division being along the broken line 9. The trimmed end 10 of the end portion 8 that is cut during this process is finally removed, together with the cut workpiece, from the pressing die.

The movable part 2b, as shown in FIG. 1, is arranged to be moved between the two end pressing dies 1, 3 and arranged to be supported on a bored block 22, A bracket 23, mounted on the frame 15, and extending in a lateral direction from the pressing dies 1, 2, 3 has a hydraulic unit 24, which is connected to the movable part 2b for moving this part to shear a workpiece.

In the left-hand side of the cross section of the pressing die 3 of the cold moulding press, the workpiece is shown before its corresponding stage of deformation. This deformation is effected with the additional use of a counter-pressure block bolster 11, which strikes directly against the workpiece contained in the die 3. Between the individual cycles of deformation in the cold moulding press, the workpiece is removed from one pressing die, transported to the next and inserted therein; if the workpiece has already attained the specified shape of the finished pressed piece, it is removed from the cold shaping press altogether.

Below the support 14, there are three hydraulic units 25, 26, 27, located on the frame 15, each of which activate a rodlike ejector unit 28, 29 and the counter-pressure block 11 which acts as an ejector unit. The ejectors 28, 29 and 11 all point in an upward direction through the support 14 into the pressing dies, 1, 2 or 3 respectively, and can be moved along their longitudinal axes.

The block 11 acting as a counter-pressure block is located on the side of the pressing die 3 opposite the pressing ram and means are provided, whereby the counter-pressure block when projecting into the bore of the pressing die can be locked in that position.

A valve 31 is located in a conduit leading to the hydraulic unit 27. When the valve 31 is opened, pressure fluid can fiow to and from the hydraulic unit 27. When the valve 31 is closed, the block or ejector unit 11 acts as a counter-pressure block and cannot be displaced in a downward direction out of the pressing die 3.

The pressing rams 18, 19, 20 are interconnected in such a way that they are all simultaneously introduced into their respective dies during each separate pressing action. The pressing ram unit is operated by a control, which, between the pressing strokes, moves the movable part 2b, which is in the shape of a shearing sleeve. The movable part 2b is moved out of the position in which it is maintained during the pressing process to shear the workpiece and then returned to its original position.

It is furthermore possible to connect the movable part 2b to the means for controlling the pressing rams in such a way that the shearing of the workpiece can be carried out in a synchronized manner between pressing strokes.

Cold moulding by means of the press shown in FIGS. 1 and 2 is best carried out in such a manner that the rough workpiece 4 is introduced into the first pressing die 1, initiating the first pressing stroke from the press, after which, by means of the hydraulic unit 16, the pressing ram 18 is forced in a downward direction in the pressing die 1. After this, the workpiece, having been subjected to the first pressing process, is removed from the pressing die 1 and the ejector unit 28 is forced in an upward direction by the hydraulic unit 25; the workpiece is transferred into the pressing die 2, while a fresh rough workpiece is fed into the pressing die 1. After the subsequent stroke of the pressing rams, the workpiece 4b contained in the pressing die 2, is cut by operation of the movable part 2b of the shearing device by means of the hydraulic unit 24. The workpiece is then transferred to the pressing die 3, while the workpiece 4a situated in the pressing die 1, is transferred to the next pressing die, i.e., pressing die 2, while at the same time a further rough workpiece 4 is fed into the pressing die 1. This is followed by a further stroke of the press, immediately after which a further shearing operation trims the workpiece 4b to its specified length. After this cycle ofoperations has been repeated, the workpiece 4c in the pressing die 3 is extracted from the press and the workpieces 4a and 4b, respectively in the pressing dies 1 and 2, are transferred to the next pressing dies, while a new rough workpiece is fed into the pressing die 1. The cold moulding process continues in this manner. The system of moulding described here can also be used with hot workpieces.

Referring to FIGS. 3 and 4, if a cold moulding operation is to be carried out on a workpiece 4c (right-hand portion of FIG. 3) with the use ofa counter-pressure block 11, as a result of which, a workpiece of the shape of 4d (left-hand portion of FIG, 4) is to be obtained, this is only possible if the workpiece 40 has been accurately cut to length beforehand, otherwise the workpiece 40 will not be in the correct position according to the illustration in FIG, 3, and as a result of this a finished pressed piece with a shape as in 42 (right-hand portion of FIG. 4) will issue. This finished pressed piece 4e differs quite clearly from the specified form as in 4d. Instead of the formation ofwrinkles 12 at the top part of the finished pressed piece 42 which is characteristic ofa faulty pressing at the junction of two parts of different cross section, a correct top part and shaft portion can be obtained by appropriate action of the ram, but in any case, a certain amount of material overlap must be expected, so that the piece as a whole would have to be considered as waste.

Referring to FIGS. 5 to 8, while the left-hand portions of FIGS. 5 and 7 show a workpiece 4c of the specified length, from which, after the pressing process, the corresponding finished pressed pieces are to be made by the partly represented pressing ram 13 and the counter-pressure block 11, the left-hand portions of FIGS. 6 and 8 show a corresponding workpiece that has not been trimmed to the correct length. From such workpieces the pressing process forms waste finished pressed pieces 42 as shown in the right-hand portions of the two Figures. Here again, the waste pressed pieces are only described by way of example and can also take other quite different shapes.

The cold moulding press in accordance with FIG. 1 may comprise more than three pressing dies, but it must have at least one shearing device generally in the form of the parts 211 and 2b. In a cold moulding press with a large number of pressing dies, the arrangement of the shearing device is in principle variable, so that in the event of any reduction in the number of pressing dies, the shearing device can be adjusted accordingly. It is possible for the press to be constructed in such a manner that the movable part 2b, which is movable between the pressing die 2 and the support 14, can be transferred to another die in the press.

I claim:

l. A press for forming stepped workpieces, comprising:

a die having a main portion defining a stepped pressing bore which has a greater size at one end thereof than at the other end thereof, said main portion comprising:

a first shear member, and

a movable portion comprising:

a second shear member adjacent said other end of the bore and movable generally perpendicularly to the axis of the bore for shearing a portion from a workpiece when contained therein,

a pressing ram arranged to move axially with respect to the bore for pushing into the bore and thereby working the workpiece, the pressing ram being disposed adjacent said one end of the bore,

ejector means adjacent said other end of the bore for removing pressed workpieces from the bore, the ejector means being arranged to move axially with respect to the bore, and

means for operating the second shear member.

2. The press defined in claim 1, wherein the second shear member defines a bore for registering with the said pressing bore.

3. The press defined in claim 1, comprising a plurality of dies each having a pressing bore, the dies being arranged sideby-side with their bores parallel, and the second shear member being arranged to be moved at right angles to the plane containing the bores.

4. The press defined in claim 1, comprising a further die having a pressing ram, means defining a pressing bore, and a counter-pressure block arranged to oppose the pressing ram of the further die from an opposite end of the workpiece, the counter-pressure block being arranged to project into the moulding bore of the further die and having means for locking the counter-pressure block therein. 

1. A press for forming stepped workpieces, comprising: a die having a main portion defining a stepped pressing bore which has a greater size at one end thereof than at the other end thereof, said main portion comprising: a first shear member, and a movable portion comprising: a second shear member adjacent said other end of the bore and movable generally perpendicularly to the axis of the bore for shearing a portion from a workpiece when contained therein, a pressing ram arranged to move axially with respect to the bore for pushing into the bore and thereby working the workpiece, the pressing ram being disposed adjacent said one end of the bore, ejector means adjacent said other end of the bore for removing pressed workpieces from the bore, the ejector means being arranged to move axially with respect to the bore, and means for operating the second shear member.
 2. The press defined in claim 1, wherein the second shear member defines a bore for registering with the said pressing bore.
 3. The press defined in claim 1, comprising a plurality of dies each having a pressing bore, the dies being arranged side-by-side with their bores parallel, and the second shear member being arranged to be moved at right angles to the plane containing the bores.
 4. The press defined in claim 1, comprising a further die having a pressing ram, means defining a pressing bore, and a counter-pressure block arranged to oppose the pressing ram of the further die from an opposite end of the workpiece, the counter-pressure block being arranged to project into the moulding bore of the further die and having means for locking the counter-pressure block therein. 